Engine fan control method and apparatus

ABSTRACT

A thermal control system for an engine and/or peripheral components is disclosed wherein a fan may be actively coupled and decoupled from an engine&#39;s shaft based on a sensed parameter such as engine temperature, alternator temperature and/or supply fuel temperature. In one embodiment, the temperature is sensed at or near the engine thermostat or peripheral component and a controller controls an electromagnetic clutch to cause the fan to engage and disengage a shaft of the engine.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional application of, and claims priority to, provisional application 60/939,006, filed on May 18, 2007, entitled “FAN CLUTCH FOR ENGINE DRIVEN GENERATORS AND WELDERS.” The specification of the provisional application is hereby incorporated in its entirety, except for those sections, if any, that are inconsistent with this specification.

TECHNICAL FIELD

Embodiments of the invention pertain to apparatuses, methods, and systems for thermal control of an engine and/or peripheral components, and more particularly to the thermal control of devices such as engine driven generators, welders, and the like.

BACKGROUND

In general, engine driven generators and welders are designed to maintain a constant revolutions-per-minute (rpm) range in order to generate a constant power supply. During use, the engine and/or various related peripheral components (e.g. fuel, alternator/generator, water pump, etc.) naturally experience a temperature increase. To control such temperature increases, the engine may include a direct drive fan to cool the engine and other components such as, for example, the radiator.

Direct drive fans are generally driven by the engine crankshaft, which results in the fan constantly pulling or pushing, depending on the fan design, the same volume and speed of air regardless of the demand for engine cooling. With the fan continuously being driven in use, the fan consumes horsepower even when the engine and radiator do not require cooling. Further, in cooler climates, the constant operation of the fan can overcool the engine resulting in a decrease in engine efficiency and a corresponding increase in fuel consumption. This also increases the emissions, as the engine may fail to reach the optimum temperature to burn the fuel properly, as well as increase noise and particulate levels.

Some generator cooling fans may be coupled to the crankshaft through a viscous clutch coupling such that the fan may be engaged and disengaged in response to sensed ambient air temperatures. Examples of such systems may be seen in U.S. Pat. Nos. 7,111,592 and 7,000,575. While these fans may disengage from the crank shaft when a certain air temperature is reached, they rely on a viscous coupling arrangement which can be unreliable in cold weather. Further, such fan arrangements rely on the ambient air temperature to determine when to engage and disengage the fan. This can lead to premature disengagement or prolonged engagement since the ambient air is not necessarily a reliable representation of the enging temperature. Further, these arrangements rely on recirculating a portion of the air back through the radiator to try and get a reading (see, e.g. 52 in the '575 patent).

DRAWINGS

Embodiments of the present invention will be readily understood by the written description along with reference to the accompanying drawing. Reference is made to the accompanying drawings which forms a part hereof, and in which is shown by way of illustration embodiments in which the invention may be practiced. Embodiments of the invention are illustrated by way of example and not by way of limitation in the accompanying drawings.

FIG. 1 illustrates a side view of an engine and fan assembly in accordance with various embodiments of the present invention;

FIG. 2 illustrates a cross sectional view of a fan assembly in accordance with various embodiments of the present invention; and

FIG. 3 illustrates a method of controlling the cooling of an engine in accordance with various embodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the following detailed description, reference is made to various embodiments including, for example, the accompanying drawing which forms a part hereof, and in which is shown by way of illustration embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments in accordance with the present invention is defined by the appended claims and their equivalents.

Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments of the present invention; however, the order of description should not be construed to imply that these operations are order dependent.

For the purposes of the present invention, the phrase “A/B” means A or B. For the purposes of the present invention, the phrase “A and/or B” means “(A), (B), or (A and B).” For the purposes of the present invention, the phrase “at least one of A, B, and C” means “(A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).” For the purposes of the present invention, the phrase “(A)B” means “(B) or (AB)”, that is, A is an optional element.

The terms “coupled,” along with its derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “coupled” may be used to indicate that two or more elements are in direct physical or electrical contact with each other. “Coupled” may also mean, however, that two or more elements are not in direct contact with each other, but yet still cooperate or interact with each other.

The description may use the phrases “in an embodiment,” “in various embodiments,” or “in embodiments,” which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, may be used with respect to embodiments of the present invention, are synonymous.

Thermal control systems in accordance with various embodiments may provide controllable cooling to keep an engine or other peripheral components (e.g. fuel supply, water pump, and/or in the case of a generator the alternator that provides the AC power for consumer use) operating at an optimum temperature in order to improve/maintain engine efficiency, even in very cold climates. In various embodiments, controlled cooling of the engine, alternator and/or supply fuel by coupling and decoupling the fan to the engine crankshaft depending on one or more situational factors (e.g. engine temp, coolant temperature, alternator temperature, supply fuel temperature, atmospheric conditions, etc.). Engine power usage, fuel consumption, emissions, or some combination thereof, may be reduced resulting, at least in part, on the fan running less than continuously. Unnecessary and/or over-cooling may also be minimized, resulting in quicker engine warm up time, particularly in cooler climates. Moreover, when the fan is not engaged for cooling, undesirable side effects such as noise and dust created by the movement of air may be minimized.

According to various embodiments of the invention, an engine may include a fan clutch for controllably coupling a fan with a crankshaft of the engine. In various embodiments, when cooling of the engine is not needed, the fan may decouple from the engine crankshaft. When cooling is needed, however, the fan may be coupled to the crankshaft until such time the engine or other sensed parameter of a peripheral component is desirably cooled, or until a predetermined amount of time has elapsed. In various other embodiments, the fan may be configured to cool a radiator coupled to the engine instead of or in addition to the engine and peripheral components; such cooling causing, at least in part, a corresponding cooling of the engine, fuel supply, alternator, and/or peripheral components.

In various embodiments, an electromagnetic fan clutch may be used to couple and decouple the fan from the crankshaft. In such embodiments, the temperature of the engine may be more accurately assessed by detecting the coolant temperature at or near the engine thermostat. Such sensing has been found to provide a more accurate and reliable temperature than simply sensing the ambient air temperature. In other embodiments, the temperature of peripheral components such as the alternator, supply fuel, water pump, etc) may be parameter that is detected directly and used to control engagement and disengagement of the fan clutch. An electromagnetic fan clutch system in accordance with various embodiments may include one or more temperature sensors coupled to the engine and/or a peripheral component, and may be configured to detect temperature of such components. In various embodiments, the system by be configured to receive existing date regarding desired parameters from a computer associated with the engine.

FIG. 1 illustrates a thermal control system for an engine in accordance with various embodiments. Engine 10 may be an internal combustion engine for use with, for example, a generator or welder. A fan 12 may be coupled to engine shaft 16 by way of an electromagnetic clutch, which may use magnetic actuation to cause frictional engagement and disengagement of clutch members. A radiator 18 may be further coupled to engine 10 and adapted provide a means for dissipating heat from an engine coolant. When coupled to the engine shaft 16, fan 12 may pull air across engine 10 and push the air through the radiator 18 as indicated by air flow 20. In various embodiments, shaft 16 may be the shaft of a water pump adapter (as illustrated), the engine crankshaft, or some other shaft that is coupled to rotate with the crankshaft.

As illustrated in FIG. 2, the electromagnetic clutch may be coupled to the engine (not shown) by way of an adapter 30. An electro magnet 32 may be disposed in rotor 34, such that both rotor 34 and electromagnet 32 are coupled to and rotate with the crankshaft of the engine. An armature 36 may be coupled to the clutch and adapted to rotate relative to the rotor 34. The armature 36 may also be non-rotatably coupled to the fan 12, which may be off set from the clutch via spacer 38. A signal source controller 24 may be coupled to the electromagnet to clutch to energize and de-energize the electromagnet.

To couple the fan 12 to shaft 16, a signal such as a voltage/current may be directed to the electromagnet 32 by signal source controller 24 to cause the electromagnet 32 to produce a magnetic field. The rotor 34 may then become magnetized, thereby creating a magnetic force that attracts the armature 36. Armature 36 may be pulled against the rotor 34 and generate a frictional engagement. The armature 36 may be accelerated to match the speed of the rotor 34, thereby engaging the fan 12. When the signal such as a current/voltage is removed from the electromagnet 32, the armature is decoupled from the shaft 16 and free to rotate independent of the rotor 34.

In various embodiments, biasing elements, such as springs, may be disposed to bias the armature away from the rotor to set up a decoupled bias when the magnet is de-energized. This not only facilitates disengagement, but also helps ensure that a sufficient gap exists between the interface surfaces of the rotor and armature to reduce residual friction. In various embodiments, the electromagnet may be disposed to magnetize and demagnetize the armature, as opposed to the rotor. In various embodiments, electromagnets may be disposed to magnetize and demagnetize each of the rotor and armature. In such embodiments, the biasing element may be a result of reversing the magnetic polarity of either the armature or the rotor can accomplish decoupling and further urging a decoupled bias until engagement is desired.

In various embodiments, a temperature sensor 22 may be coupled to the engine 10 and adapted to sense the temperature of the engine and/or coolant within the engine (sensed parameter). Signal source controller 24 may be coupled to the sensor 22 and further coupled to the electromagnet 32 of clutch 14. Controller 24 may receive the sensed temperature/parameter from sensor 22 and determine whether the sensed temperature exceeds a preset threshold. If yes, then the controller 24 may cause a signal to be sent to the electromagnet 32, thereby coupling fan 12 to the shaft 16 as previously described. Once the temperature drops below the threshold level, then the controller may cause the clutch 14 to disengage thereby stopping the fan 12.

In various embodiments, a power or signal source 26 (e.g. a battery) may be coupled to the sensor 22, signal source controller 24 and/or electromagnetic fan clutch 14. When the sensed temperature of the engine and/or coolant reaches the predetermined set point, a supply voltage may be directed to the electromagnet 32, thereby coupling the fan 12 to the shaft 16. When the engine and/or engine coolant is cooled by the fan to the predetermined set point or when a certain duration has elapsed, for example, the supply voltage to the clutch 14 may be interrupted, thereby decoupling the fan 12 from the crankshaft 16.

In various embodiments, the signal source controller may be a thermally-controlled switch (thermal switch) that includes a temperature probe (e.g. sensor 22) coupled to the engine's thermostat. The thermal switch may sense the coolant temperature and/or whether the thermostat is open or closed. The thermal switch may further be set with a predetermined temperature and/or temperature range for coupling and decoupling the fan to the crankshaft. In various embodiments, the temperature range for the controller may be correlated with the temperature range used for the thermostat. For example, the controller may be configured to cause engagement of the clutch 14 when the temperature of the coolant gets to be more than 5-15 degrees above the thermostat full open range.

In various embodiments, the sensed parameter may be a temperature of one or more peripheral components such as an alternator and/or the fuel supply. In such embodiments, a sensor may detect the temperature of the alternator and/or the supply fuel. When the sensed temperature exceeds a certain threshold, the signal source controller may direct a signal to the clutch to cause engagement and/or disengagement to cool the alternator and/or the supply fuel cooler. In various embodiments, either a single sensed parameter may be used to dictate actuation and de-actuation of the fan. In various other embodiments, two or more sensed parameters may be used to control fan coupling.

In various embodiments, the signal source controller may include a computer that may be programmed with desired thresholds for engaging and disengaging of the clutch. For example, in one embodiment using an electromagnetic fan clutch, the controller may receive an input from a thermostatic variable resistor that is in contact with the engine coolant, fuel supply, alternator, etc. A predetermined resistance value from the sensor may control the ground circuit of the electromagnet. When the resistance value from the temperature sensor reaches the set threshold the controller grounds the electromagnet's ground circuit, which creates a magnetic field coupling the rotor and armature together (discussed above). Once the resistance value from the temperature sensor is outside of the predetermined value the ground circuit to the electromagnet is then opened thus causing the magnetic field to disperse and allowing the armature to turn freely from the rotor, thereby disengaging the fan.

FIG. 3 illustrates a block diagram of a method for thermally controlling an engine. In various embodiments, a sensor may continuously or periodically sense the temperature of the engine and/or engine coolant 200. A controller may direct signals to an electromagnetic fan clutch, thereby either coupling or decoupling a fan from the crankshaft of an engine 210. Continuing to couple and decouple the fan with the crankshaft based on the sensed temperature with respect to a predetermined threshold and/or range 220. In various embodiments, a different parameter may be sensed, such as alternator temperature and/or supply fuel temperature.

In various embodiments, the method may further include using a thermal switch to control the directing of a reference voltage to the fan clutch. In various embodiments, the controller may include a computer or other programmable device which allows a user to input desired temperature ranges for when to couple and decouple the fan from the engine crankshaft.

According to some embodiments, the fan clutch may be configured with a default-locked, default-unlocked configuration, or may be configured without a default setting. Other parameters may be used in addition to or instead of such temperature set points. For example, various embodiments may be configured to controllably couple and decouple the fan based at least in part on time intervals. For example, a fan clutch may be configured to only couple the fan to the crankshaft every n seconds/minutes/etc., where n is a predetermined and changeable value. Thus, n may then be altered based on ambient conditions such as temperature, humidity, moisture, etc.

Further, in various embodiments, the fan clutch may be a viscous-actuated fan clutch, or a similar apparatus. In such embodiments, based on the temperature of the engine or other peripheral component (e.g. as taken from a sensor detecting coolant temperature at or near the thermostat, the alternator temperature, and/or the supply fuel temperature), the controller sends a signal to the fan clutch causing the actuation of a valve to control movement of the viscous fluid, thereby causing engagement or disengagement of the clutch with the shaft.

Embodiments in accordance with the present invention may be suitable for engines including any one or more of various fan types. For example, some fans are a pusher-style fans that push air through the radiator and/or associated components. Puller-style fans are also known, which pull air through the radiator, over an engine and/or associated components. The embodiment illustrated in the drawings depicts a system including a pusher-style fan, where the air is pulled over the engine and pushed through the radiator.

Although certain embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope of the present invention. Those with skill in the art will readily appreciate that embodiments in accordance with the present invention may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments in accordance with the present invention be limited only by the claims and the equivalents thereof. 

1. A thermal control device for engines and engine components, comprising: a fan positioned to cool an engine and/or peripheral components; a clutch disposed between the fan and the engine, the clutch is coupled to the fan and a shaft of the engine; a sensor adapted to sense a parameter of the engine and/or one or more of the peripheral components; and a controller adapted to receive the sensed parameter from the sensor and send a signal to the clutch to cause the clutch to either engage or disengage the fan with the shaft.
 2. The thermal control device of claim 1, wherein the sensed parameter is engine temperature and wherein the sensor is coupled to a thermostat of the engine and adapted to sense the temperature of the engine coolant.
 3. The thermal control device of claim 1, wherein the sensed parameter is thermostat position, and wherein the sensor is coupled to a thermostat of the engine and adapted to sense whether the thermostat is open or closed.
 4. The thermal control device of claim 1, wherein the sensor is coupled to an alternator and the sensed parameter is an alternator temperature.
 5. The thermal control device of claim 1, wherein the sensor is coupled to a fuel supply, and the sensed parameter is supply fuel temperature.
 6. The thermal control device of claim 1, wherein the sensed parameter is ambient temperature or humidity.
 7. The thermal control device of claim 1, further comprising a signal source coupled to the controller and the clutch, and wherein the controller is adapted to control when the signal source sends a signal to the clutch to control the coupling and decoupling of the fan to the shaft.
 8. The thermal control device of claim 1, wherein the clutch includes: a rotor coupled to the shaft and adapted to rotate with the shaft; an armature proximally disposed to the rotor and adapted to rotate relative to the rotor and wherein the fan is coupled to and rotates with the armature; and an electromagnet disposed on the rotor and/or armature, the electromagnet adapted to receive the signal from the controller to magnetize and de-magnetize the rotor and/or armature.
 9. The thermal control device of claim 8, further comprising a biasing element adapted to urge the armature and the rotor to be spaced apart relative to each other.
 10. The thermal control device of claim 9, wherein the biasing element is a spring or a magnetic field.
 11. A method of thermally controlling the temperature of an engine or peripheral component, comprising: sensing a parameter of the engine and/or peripheral component; sending a signal representative of the parameter to a controller; based on a predetermined parameter threshold, effecting a control signal on a fan clutch; and selectively coupling and decoupling a fan to an engine shaft based on the effected control signal.
 12. The method of claim 11, further comprising providing an electromagnetic fan clutch to control the selectively coupling and decoupling of the fan to the engine shaft.
 13. The method of claim 11, wherein the effecting a control signal includes sending a voltage or current to the fan clutch.
 14. The method of claim 11, further comprising setting the predetermined parameter threshold based on the atmospheric conditions.
 15. The method of claim 11, wherein the sensing the parameter includes sensing the temperature of an engine coolant at an engine thermostat.
 16. The method of claim 11, wherein the sensing the parameter includes sensing the temperature of an alternator.
 17. The method of claim 11, wherein the sensing the parameter includes sensing the temperature of a supply fuel.
 18. A method of thermally controlling the temperature of an engine or peripheral components, comprising: providing a controller coupled to a fan clutch; setting a desired time interval for which to have the clutch couple a fan to an engine shaft; based on a set time interval, effecting a control signal on a fan clutch; and selectively coupling and decoupling a fan to an engine shaft based on the effected control signal. 